Shengyang Yang

Passive tumor targeting of renal-clearable luminescent gold nanoparticles: Long tumor retention and fast normal tissue clearance

Glutathione-coated luminescent gold nanoparticles (GS-AuNPs) with diameters of ∼2.5 nm behave like small dye molecules (IRDye 800CW) in physiological stability and renal clearance but exhibit a much longer tumor retention time and faster normal tissue clearance, indicating that the well-known enhanced permeability and retention effect, a unique strength of conventional NPs in tumor targeting, still exists in such small NPs. These merits enable the AuNPs to detect tumor more rapidly than the dye molecules without severe accumulation in reticuloendothelial system organs, making them very promising for cancer diagnosis and therapy.

PEGylation and Zwitterionization: Pros and Cons in the Renal Clearance and Tumor Targeting of Near‐IR‐Emitting Gold Nanoparticles

PEGylation is the most common and successful surface-chemistry strategy for reducing nonspecific accumulation and prolonging blood circulation of inorganic nanoparticles (NPs), so that the NPs can effectively target tumors through well-known “enhanced permeability and retention (EPR)” effect.[1] These strengths fundamentally arise from the fact that poly(ethylene glycol) (PEG) moiety on the particle surface creates steric hindrance for the serum protein (opsonin) adsorption and slows down the NP uptake by the reticuloendothelial system (RES) organs (liver, spleen etc.).[2] However, the majority of PEGylated NPs still end up in RES organs after the circulation,[3] resulting in low targeting specificity (defined as the amount of NPs in tumor vs that in liver).[4] For instance, even though PEGylated AuNPs with a 2 nm core size can circulate in the body at a high concentration, they were found to severely accumulate in the liver (78 %ID/g) and spleen (15.2 %ID/g) at 24 h post-injection (p.i.).[5] Such long-term severe accumulation in RES potentially induces health hazards, hampering their clinical translation. Therefore, developing PEGylated inorganic NPs that not only can retain strong EPR effect but also can be eliminated from the urinary system like clinically used small molecular contrast agents[6] is highly desired but remains a big challenge.

Interface-Directed Assembly of One-Dimensional Ordered Architecture from Quantum Dots Guest and Polymer Host

Assembly of inorganic semiconductor nanocrystals into polymer host is of great scientific and technological interest for bottom-up fabrication of functional devices. Herein, an interface-directed synthetic pathway to polymer-encapsulated CdTe quantum dots (QDs) has been developed. The resulting nanohybrids have a highly uniform fibrous architecture with tunable diameters (ranging from several tens of nanometers to microscale) and enhanced optical performance. This interfacial assembly strategy offers a versatile route to incorporate QDs into a polymer host, forming uniform one-dimensional nanomaterials potentially useful in optoelectronic applications.

A Release‐Induced Response for the Rapid Recognition of Latent Fingerprints and Formation of Inkjet‐Printed Patterns

Fingerprints are widely used for personal identification in numerous fields, such as forensic investigation, 3] law enforcement, access control, or medical diagnostics. A latent fingerprint, an impression of the ridge pattern of a human finger, is formed on a surface when a finger touches the surface, and it is usually invisible in daylight. Various elegant physical (powder dusting, small particle reagent, metal deposition), chemical (iodine, cyanoacrylate, ninhydrin, and their analogues), spectroscopic (laser, fluorescence, mass spectrometry, and UV/Vis and infrared absorption), and combination techniques have been explored for the visualization or enhancement of latent fingerprints (LFPs) under specific circumstances. 8] Among those reported, several efforts for intelligent LFPs detection are of particular interest. Russell and co-workers devised a smart combined route to simultaneously identify drug metabolites and fingerprints based on antibody-functionalized nanoparticle deposition. They also demonstrated that antibody–magnetic-particle conjugates can be applied to the fast imaging of LFPs within 15 min. Almog et al. employed the natural product genipin as a safer and benign reagent to develop LFPs with both color and fluorescence. A nondestructive example of fluorescence imaging was reported recently in which LFPs were successfully transferred to a fluorescent conjugated polymer film. Despite amazing achievements that have been made in LFPs recognition, it is still a great challenge to develop LFPs in a technically simple, rapid, and easy handling way. To this end, we demonstrate herein a new easy-toperform and versatile strategy that enables ultrafast identification of LFPs on various surfaces by using commercial thermoplastic polyurethane (TPU) resin and an electrospinning technique with a release-induced response (RIR) process. The nondestructive collection and identification of LFPs on various surfaces were carried out using an electrospun TPU/fluorescein nanofiber mat. LFPs on various surfaces were transferred easily onto the electrospun mat by softly pressing the mat on the surfaces, and then these LFPs were immediately visualized (30 s) in red under daylight after exposing the mat to hot air (100 8C). This relatively simple method overcomes the disadvantages in most current LFP detection techniques, which usually require laborious pre-/ post-treatments, suffer from contaminative reagents (liquids, powders, and chemical fuming), or involve various sophisticated spectroscopic instruments. The approach offers the advantage that the identification of LFPs can be easily achieved within seconds under daylight. Also, this portable electrospun mat is a valuable tool for fingerprint examiners that allows them to rapidly, facilely, and nondestructively lift fingerprints from various surfaces without pre-treating fingerprints. We also show that this phenomenon can be ascribed to a typical release-induced response (RIR) process. A crosslinking behavior exists between TPU and the residues of fingerprints, which induces phase separation between TPU network and fluorescein. This separation allows fluorescein to be released from TPU nanofibers easily, conferring a color variation. To further validate this RIR mechanism, we also show that the versatile patterns on these electrospun mats can be followed by the RIR procedure and fabricated by a jet printer using water as an “imaging ink”, along with tertiary amine catalyst for accelerating cross-linking process. To the best of our knowledge, this is the first example of the utilization of an electrospun mat for the identification of LFPs and formation of inkjet-printed patterns, which may be extended to explore microreactors, multifunctional combined sensors, and also versatile detection/analysis devices. Figure 1 shows the schematic procedure for fabrication of the sensor mat for fingerprints. The electrospinning technique, a cost-effective and versatile approach for facile generation of fibrous polymer mats with the virtue of large surface area, was employed to prepare a homogeneous blend of TPU and fluorescein with a nanofiber structure (Figure 1A). Given that TPU is a multiblock copolymer with thermodynamic incompatibility of hard segments and soft segments, a solvent mixture of DMF/THF was chosen to avoid microphase-separated morphology. The resulting homogeneous TPU/fluorescein solution was electrospun into nanofibers that were collected on the surface of a grounded rotating drum to obtain a uniform straw-colored mat (Figure 1B, inset; Supporting Information, Figure S1–S3, Table S1). A scanning electron microscope (SEM) image of a fresh TPU/fluorescein mat without LFPs shows that the fiber structures in the mat have a highly uniform size distribution with an average diameter of about 300 nm (Figure 1B). Interestingly, one donor deposited an LFP on the electrospun [*] S. Y. Yang, Dr. C. F. Wang, Prof. S. Chen State Key Laboratory of Material-Oriented Chemical Engineering and College of Chemistry and Chemical Engineering Nanjing University of Technology Nanjing, 210009 (P.R. China) Fax: (+ 86)25-8317-2258 E-mail: chensu@njut.edu.cn

Superhydrophobic Thermoplastic Polyurethane Films with Transparent/Fluorescent Performance

In this paper, we report a simple and versatile route for the fabrication of superhydrophobic thermoplastic polyurethane (TPU) films. The approach is based on octadecanamide (ODAA)-directed assembly of nanosilica/TPU/ODAA hybrid with a well-defined sheetlike microstructure. The superhydrophobic hybrid film shows a transparent property, and its water contact angle reaches as high as 163.5° without any further low surface energy treatment. In addition, the superhydrophobic TPU hybrid film with fluorescent properties is achieved by smartly introducing CdTe quantum dots, which will extend potential application of the film to optoelectronic areas. The resulting fluorescent surface produced in this system is stable and has a water contact angle of 172.3°. This assembly method to control surface structures represents an intriguing and valuable route to tune the surface properties of organic-inorganic hybrid films.

Magnetic-Directed Assembly from Janus Building Blocks to Multiplex Molecular-Analogue Photonic Crystal Structures

The predictable assembly of colloidal particles into a programmable superstructure is a challenging and vital task in chemistry and materials science. In this work, we develop an available magnetic-directed assembly strategy to construct a series of molecular-analogue photonic crystal cluster particles involving dot, line, triangle, tetrahedron, and triangular bipyramid configurations from solid-liquid Janus building blocks. These versatile multiplex molecular-analogue structural clusters containing photonic band gap, fluorescent, and magnetic information can open a new promising access to a variety of robust hierarchical microstructural particle materials.

Controllable synthesis of quantum dot–polymer networks with enhanced luminescence via the catalytic chain transfer polymerization (CCTP) technique

We report on a new available strategy for fabricating CdS QD–polymer hybrids networks with enhanced photoluminescence (PL). Firstly, we synthesized a series of versatile polymeric ligands for the preparation of nanocrystals by catalytic chain transfer polymerization (CCTP) and radical addition–fragmentation polymerization (RAFT) methods. With these versatile polymeric ligands containing a large number of anchors and double bond functional groups, CdS QD–polymer networks were fabricated by the intramolecular cross-linking interaction between the polymeric ligands on the surfaces of each CdS nanocrystal. The as-prepared QD–polymers herein exhibit stable and highly enhanced PL properties relative to their PL before cross-linking. In addition, by measuring the changes of PL intensity, we found the PL intensity of QD–polymers demonstrated remarkable enhancement after 7 months. Related mechanisms were briefly discussed.

Luminescent gold nanoparticles: A new class of nanoprobes for biomedical imaging

Our fundamental understanding of cell biology and early diagnosis of human diseases have been greatly benefited from the development of fluorescent probes. Over the past decade, luminescent gold nanoparticles (AuNPs) with diverse structural parameters including particle size, surface ligands, valence state and grain size have been synthesized and have begun to emerge as a new class of fluorescent probes for bioimaging because of their great biocompatibility, robust photophysical properties and tunable emissions from the visible range to the near infrared region. In this minireview, we summarize the recent progress in applications of different-sized luminescent AuNPs as imaging probes for both in vitro and in vivo levels.

Zinc ion-doped carbon dots with strong yellow photoluminescence

We demonstrated a simple strategy for facile generation of high-quantum yield robust yellow photoluminescent (PL) carbon dots (CDs) doped with zinc ions. These as-synthesized CDs when synthesized using zinc ions and citric acid as the precursor via a one-pot solvothermal method produced zinc ion-doped CDs that yielded excitation-independent yellow PL emission and the highest QY reported to date of 51.2%. We also thoroughly discuss the formation mechanism of these CDs, whose high quality was attributed to the radiative recombination of electrons and holes trapped on the CD surface. We also showed the ability to find practical applications of these as-prepared CDs, such as for bifunctional photonic crystal films and for fluorescent microfibers and patterns.

Glutathione-Coated Luminescent Gold Nanoparticles: A Surface Ligand for Minimizing Serum Protein Adsorption

Ultrasmall glutathione-coated luminescent gold nanoparticles (GS-AuNPs) are known for their high resistance to serum protein adsorption. Our studies show that these NPs can serve as surface ligands to significantly enhance the physiological stability and lower the serum protein adsorption of superparamagnetic iron oxide nanoparticles (SPIONs), in addition to rendering the NPs the luminescence property. After the incorporation of GS-AuNPs onto the surface of SPIONs to form the hybrid nanoparticles (HBNPs), these SPIONs’ protein adsorption was about 10-fold lower than those of the pure glutathione-coated SPIONs suggesting that GS-AuNPs are capable of providing a stealth effect against serum proteins.